The invention relates to a device for transporting and positioning wafer-type workpieces and, in particular, semiconductor wafers, in which the workpieces are moved, with the aid of fluid media, across a guideplate provided with lateral walls, the media being forced through nozzles, which are arranged in the plate bottom and inclined in the direction of transportation, into a transportation space in which at least one region is provided for retarding and positioning the workpieces. It furthermore relates to a process for the wet-chemical surface treatment of wafer-type workpieces and, in particular, semiconductor wafers, in which one or more liquids are caused to act on the wafer surface and the wafers are subjected to at least one transportation operation by means of fluid media.
A device of the type generally mentioned above is known from DE-B-2,036,337, filed Jul. 22, 1970, claiming priority of U.S. application Ser. No. 844,918, filed Jul. 25, 1969 (Applicant--Texas Instruments Inc.). In that case, pressurized gaseous or, alternatively, liquid media, and normally air, is used as a transportation means. For the purpose of retardation, the workpieces are brought into contact with a retarding surface at a point provided, so that the speed is first reduced by mechanical friction until the wafers come to rest near a specified point and can ultimately be brought into their final position. However, such a contact with retarding surfaces may, in itself, result in an impermissible contamination of the workpieces, and this applies, in particular, to semiconductor wafers on which extremely high cleanliness requirements are imposed by the component manufactures. In addition, this device permits only translational movements of the wafers, but not rotational ones.
EP-B-130,866 and the corresponding U.S. Pat. No. 4,557,785 disclose a further device of this type, in which, after an etching and rinsing treatment by means of nozzles carried out with rotation in an etching station, the wafers are transported through a rinsing bath and eventually transferred to a spin-drier in which adhering water is spun off, so that the dried wafers eventually obtained can then be removed for the next treatment step. Both the introduction of the wafers into the etching station and also the retardation of the wafers on introduction into the spin-drier and the dry spinning are carried out in this case with mechanical aids, so that a contamination of, or damage to, the wafers cannot be ruled out. In addition, the etching station has to be opened in each case to introduce or remove the wafer by mechanically moving its cover, and this, of course, also implies the risk of a contamination due to abrasion. A further disadvantage is that the etching station is loaded alternately with etchant and water, so that an entrainment of reagent residues is possible.